$ { \left[\begin{array}{rrr}{2} & {-2} & {1} \\ {-2} & {2} & {3}\end{array}\right]+\left[\begin{array}{rrr}{1} & {1} & {-2} \\ {-1} & {3} & {0}\end{array}\right] = {?} } $
Explanation: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{2}+{1} & {-2}+{1} & {1}+{-2} \\ {-2}+{-1} & {2}+{3} & {3}+{0}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{3} & {-1} & {-1} \\ {-3} & {5} & {3}\end{array}\right]}$